How to make full screen !!!! game - why is my screen limited to 640 by 960 ?????

I've been pulling my hair out over this too.

Turns out the main issue is that the example Metal project doesn't set a launch screen - and iOS way back when used the lack of launch screen images as a signal that your app wasn't compatible with the iPhone 5's taller aspect ratio...

Just using New->File...->Launch Screen and setting it in the "General" tab of the target setting made the view full-screen for me.

One other annoyance that I can't figure out is the view doesn't rotate despite the orientations being set in the Info.plist. Might be to do with the sample still just AppDelegate and not adopting the new UIScene stuff, but I'm sure I've seen rotation work still in other apps as expected.

And I've now tracked down the auto-rotation issue, and it's another weird one...

I noticed it was only happening when Xcode was debugging the app, not when it was started manually.

A simple non-metal app worked fine, and I finally discovered that if I removed the Renderer.m from the app target and commented out the code that referenced it gave an app where rotation of the view controller worked as expected.

Looking at the debugger output, I noticed the "Metal GPU Frame Capture Enabled" line only appeared on the output when the Renderer.m code was linked in (even if it wasn't called) and that seemed to correlate with when auto-rotation didn't work.

That was enough to find this post: https://developer.apple.com/forums/thread/656241 which contains the solution - setting the "GPU Frame Capture" found in (Scheme -> Run -> Options page) to either "Metal" or "Disabled" fixes this bug and allows auto-rotation to work when the app is being debugged.